1. Field of the Invention
The present invention relates to a display device, and particularly, to a simplified method of fabrication a color filter in a liquid crystal display device having a reduced fabrication cost.
2. Description of the Related Art
The ongoing development of various portable electric devices such as mobile phones, PDAs, notebook computers, etc. requires concomitant development of thin and small flat panel display devices. Liquid crystal displays (LCD), plasma display panels (PDP), field emission displays (FED), and vacuum fluorescent displays (VFD), for example have all been actively researched for use as the flat panel display, however, the LCD is generally used due to its advanced mass production technology, the easy of driving the devices, and realization of high image quality.
FIG. 1 is a view showing a cross-section of a general liquid crystal display device. As shown therein, the liquid crystal display device 1 comprises a first substrate 5, a second substrate 3, and a liquid crystal layer 7 formed between the first substrate 5 and the second substrate 3. The first substrate 5 is a driving device array substrate, and a plurality of pixels are formed on the first substrate 5 and a driving device 9 such as a thin film transistor is formed on the respective pixel. The second substrate 3 is a color filter substrate, and a color filter layer 2 for realizing actual colors and a black matrix 8 for blocking light leakage are formed thereon. Also, a pixel electrode 6 and a common electrode 4 are formed on the first substrate 5 and the second substrate 3 respectively, and an alignment layer (not shown) for orienting liquid crystal molecules of the liquid crystal layer 7 is applied thereon.
The liquid crystal display device constructed as above is formed by a driving device array substrate process and a color filter substrate process respectively.
The driving device array substrate process forms a plurality of gate lines and data line arranged on the lower substrate 5 for defining pixel areas, forms the thin film transistor 9, that is, the driving device connected to the gate line and to the data line on respective pixel area, and after that, forms a pixel electrode connected to the thin film transistor 9 for driving the liquid crystal layer according to a signal application through the thin film transistor.
Also, the color filter process forms the black matrix on the upper substrate 3, forms the color filter 2 on upper part of the black matrix 8, and forms the common electrode 4 on the color filter 2.
Different methods exist for fabricating the color filter, such as a pigment dispersing method and an electrophoresis deposition method. The pigment dispersing method forms the color filter by coating, exposing, developing and burning pigment composition dispersed on a photoresist. Fabrication of the color filter using the pigment dispersing method will be described with reference to FIGS. 2A to 2D.
First, as shown in FIG. 2A, a transparent substrate 21 is prepared, material for forming black matrix, such as chrome and organic material, is coated on the substrate 21, and after that, a black matrix pattern 22 is formed using a photolithographic process that includes a photo mask. As shown in FIG. 2B, materials for forming red (R) color filter layer 23 are coated on the substrate 21 and black matrix pattern 22. A predetermined area is the exposed using a photo mask 28 and developed to form the R color filter layer 23a as shown in FIG. 2C. After that, the above process is repeated using different materials to form the green (G) and blue (B) color filters layers 23b and 23c, as shown in FIG. 2d. 
However, in the fabrication method used to form the color filters according to the related art, not only are expensive photo masks used, but in addition, the photolithographic processes, which include the color filter coating, exposure, and development, are repeatedly performed to create the color filter. The expense of the photo masks as well as the time and costs associated with multiple fabrication steps increase the overall fabrication costs in forming the layer containing the color filters.